This application claims the priority of German application 198 52 944.9, filed in Germany on Nov. 17, 1998, the disclosure of which is expressly incorporated by reference herein.
The invention relates to an adaptive flow body, especially an aircraft wing, with a variable wing profile, including a rigid middle part and leading and trailing edges fastened thereto, with a flexible cladding covering the front and/or rear parts, and structural elements mounted in the front and/or rear parts driven by actuators which act on the flexible cladding.
To adapt an aircraft wing in terms of its lift, flow resistance, and controlling effect to various flight states such as takeoff, cruising, maneuvering, and landing phases, various solutions are known that are based on an adaptive change in the profile of the wing itself. The wings are therefore partially provided with flexible cladding which is acted upon inside the wing through actuators using adjustable structural elements.
In an adaptive wing of this type described in German Patent Document No. DE-A1-196 43 222 corresponding to pending U.S. patent application Ser. No. 08/954,198, filed Oct. 20, 1997, the rear flexible area of the wing has its camber changed by means of adjusting bodies curved in their lengthwise axes, by rotating the adjusting bodies around their lengthwise axes. The adjusting bodies are provided over their lengthwise axes with variable cross sections so that the local cross section of the adjusting body corresponds to the profile thickness of the wing. Each adjusting body is in contact at least areawise with the flexible cladding, directly and/or by a thin sliding layer. The tilting moments that appear in the adjusting bodies that are mounted on one side require costly mounting whose arrangement uses the rigid spar of the wing. The flexible cladding is connected with the rigid forward part of the wing by bolts. The wing can be adapted to various operating states by the known solution only by changing the camber of the wing profile. Changing the camber allows the lift and flow resistance of a wing to be influenced and no additional controlling effects can be achieved in this manner.
Another wing is known from German Patent Document No. DE-A-20 26 054 with a variable wing profile camber. For this purpose, flexible cladding is provided in the front and rear areas of the wing on which rib parts act to change the camber of the wing, said ribs being pivotably mounted on the spar of the wing and driven by actuators to perform a pivoting effect. In addition to the pivotable rib parts, struts mounted with articulation act on the flexible cladding to maintain the wing profile cross section with changing camber. These struts are connected with articulation to the flexible cladding on the one hand and with articulation to the rigid receptacles for the pivotable rib parts on the other. No actuators act on the struts; their positions are altered by the connection of the cladding with the pivoting of the rib parts and they act as supporting elements only. As in the prior art described above, in this wing as well, the rib parts acting as adjusting bodies are mounted on the rigid spar. The flexible cladding has discontinuities at the transitions to the rigid cladding, in the form of movable bearings, and the wing can be adapted only in terms of its camber.
A goal of the invention is to create an adaptive flow body whose profile can be adapted to different operating requirements involving lift and crosswind, flow resistance, and control.
This goal is achieved according to the invention by providing an adaptive flow body including a rigid middle part and leading and trailing edges fastened thereto, with a flexible cladding covering the front and/or rear parts, and structural elements mounted in the front and/or rear parts driven by actuators which act on the flexible cladding, wherein the rear part is divided into two rear partial profiles by means of a slot that begins at a trailing edge and penetrates in a lengthwise direction of the flow body profile toward the middle part, wherein these rear partial profiles each also have a flexible inner skin, wherein flexible outer skins are fastened continuously to the middle part, wherein an actuator acts on each inner skin with pushing or pulling movements transmitted by joints from the inner skin to inner rear structural elements which transmit these movements through rigid connections as bending moments to the outer skin.
The flow body according to the invention consists essentially of three parts, the leading edge, a rigid middle part adjacent thereto, and a rear trailing edge. The trailing and/or leading edges are each divided into two adjacent forward or rear partial profiles with a slot that begins at the leading or trailing edge and penetrates in the lengthwise direction of the flow body profile to the rigid middle part, said partial profiles being covered by inner skins up to the slot. The inner skins make a transition to the trailing or leading edge in the outer skins of the partial profiles.
The partial profiles have profile camber that can be controlled by actuators that act on their inner skins by pushing and pulling movements. These pushing and pulling movements are transmitted as bending moments to the outer skins by means of structural elements located in the partial profiles, each of which is mechanically connected with articulation with the inner skin and rigidly with the outer skin. As a result, a variable camber which can be individual for each partial profile required can be set as a function of the extent of the pushing and pulling movements.
The invention has the advantage that a combination of differently cambered partial profiles on the rear part permits additional control functions and the achievement of air brake effects without the usual use of control or brake flaps. The actuators can be accommodated almost without any moments in the wing, since the moments of partial profiles that belong together cancel each other out. At the transitions from the front part to the middle part and from the middle part to the rear part, there is a closed outer skin which, with a camber of the partial profiles, has a continuous path of curvature instead of a sharp angle when the flaps are set. Another advantage of the invention consists in the fact that the structural elements that act on the movable outer skins and the actuators do not have to be located in the rigid middle part, for example in a wing spar. As a result, a modular design can advantageously be obtained which allows good maintenance by means of replaceable modules consisting of the partial profiles with their individual actuators and structural elements. The system can be locked in each profile position and secured forcewise with selectable forces to the actuating mechanism with the desired pressure. For adjustment, this force fit can be released or reduced. Advantageously, a choice of different actuators is contemplated. It is contemplated to use hydraulics, a hydraulic motor with a spindle, pneumatics, or mechanical kinematics. No bearings, or only bearings that require little maintenance are required for the actuators and structural elements. One improvement on the invention shows a two-stage design of one of the two rear profile halves. Therefore, it is advantageously possible to provide extra control for the end areas of the profile.